1. Field of the Invention
This invention relates to a method and apparatus for testing a cold gas at temperature below about -10.degree. F. for the presence of a hazardous gas.
2. Brief Description of Prior Art
In colder climates, difficulty is frequently encountered in testing gaseous mixtures for the presence of hazardous gases. Such hazardous gases may comprise hydrogen sulfide, carbon monoxide, chlorine, light hydrocarbon gases which can constitute an explosive mixture with air, nitrogen oxides, sulfur oxides, carbon dioxide, mercaptans, other heteroatom-containing gases, mixtures thereof and the like. Portable test equipment has been developed and is widely used for testing gases, such as air, to determine whether hazardous gases are present in warmer climates. Unfortunately, such test apparatus has been found to be ineffective and unreliable in colder climates, particularly in very cold climates where temperatures of -20.degree. to -50.degree. F. and colder are encountered. It is desirable to be able to test gases for the presence of hazardous gases at such temperatures prior to the entry of workers and the like into the environment. Since the portable test apparatus used in warmer climates is ineffective at the colder temperatures, it has been necessary to develop other more complicated means for performing these tests. As a result, it has been difficult to obtain timely and frequent tests as necessary to ensure the safety of the atmosphere in working environments in colder climates.
Since it is highly desirable that means for promptly and reliably testing such environments for the presence of hazardous gases be available, a continuing effort has been directed to the development of test apparatus by which such tests can be quickly and reliably performed.